Russia's Defence Ministry denied Tuesday that Russian or Syrian aircraft carried out a strike that hit a UN humanitarian aid convoy in Syria's Aleppo province, state-run TASS news agency reported.
"All information about the convoy's whereabouts was known only to the militants who control these areas," the ministry statement said, appearing to blame rebel forces for the attack. No rebel factions in Syria have an air force.
The US - which has also carried out raids in Syria - charged that either Russian or Syrian planes carried out the strike on the convoy, which the Red Cross said killed 21 people late Monday, just hours after the Syrian army declared the end of a week-long ceasefire.
The attack on the convoy led the UN to halt all aid deliveries in Syria and has drawn the condemnation of the international humanitarian community.
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A UN humanitarian aid convoy was attacked near Aleppo on Monday as a week-long ceasefire in Syria brokered by Russia and the United States collapsed.
The United Nations suspended all humanitarian convoys in Syria Tuesday after 21 people died in what UN Secretary General Ban Ki-moon called a "sickening, savage and apparently deliberate attack" on vehicles delivering aid.